/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.dx.io.instructions;

import java.io.EOFException;

/**
 * Implementation of {@code CodeInput} that reads from a {@code short[]}.
 */
public final class ShortArrayCodeInput extends BaseCodeCursor implements
		CodeInput {

	/** source array to read from */
	private final short[] array;

	/**
	 * Constructs an instance.
	 */
	public ShortArrayCodeInput(short[] array) {
		if (array == null) {
			throw new NullPointerException("array == null");
		}

		this.array = array;
	}

	/** @inheritDoc */
	public boolean hasMore() {
		return cursor() < array.length;
	}

	/** @inheritDoc */
	public int read() throws EOFException {
		try {
			if (cursor() >= array.length)
				throw new ArrayIndexOutOfBoundsException(cursor());
			int value = array[cursor()];
			advance(1);
			return value & 0xffff;
		} catch (ArrayIndexOutOfBoundsException ex) {
			String reason = "class " + this.getClass().getName()
					+ " array size " + array.length + " cursor " + cursor();
			EOFException exception = new EOFException(reason);
			exception.initCause(ex);
			throw exception;
		}
	}

	/** @inheritDoc */
	public int readInt() throws EOFException {
		int short0 = read();
		int short1 = read();

		return short0 | (short1 << 16);
	}

	/** @inheritDoc */
	public long readLong() throws EOFException {
		long short0 = read();
		long short1 = read();
		long short2 = read();
		long short3 = read();

		return short0 | (short1 << 16) | (short2 << 32) | (short3 << 48);
	}
}
